Telephone-exchange system.



E. E. HINRICHSEN.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JUNE 12. 1915.

1,1 61,21 Patented Nov. 23, 1915.

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EDWARD E. HINRIGI-ISEN, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

TELEPHONE-EXCHANGE. SYSTEM.

To all whom it may concern: 7

Be it known that I, EDWARD E. HINnIoH- SEN, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and more particularly to such systems in which common battery and magneto telephone lines terminate at the same position of a switchboard at a central oiiice, such lines being adapted to be connected with lines terminating at another position of the same or different switchboard.

It is an object of this invention to provide an improved trunk circuit by means of which connection may be made between a link connecting circuit on the one end and either a common battery or magneto telephone line on the other end, and over which supervision may be had from either character of local telephone line to the link con necting circuit.

In telephone exchange systems heretofore used, where common battery and magneto lines terminate on the same switchboard, several methods have been in use for furnishing service between these lines and toll lines. Where the toll board'is a part of the local switchboard, one method which has been in use is to multiple all of the local linesboth common battery and magnetothrough the various toll positions, andto use toll cords one end of which would distinguish between the common battery and magneto lines.

Where the toll board is separate and distinct from the local board, one method in use is to use trunks terminating in jacks at both boards, to use at the toll board cords which distinguish between tolland trunk lines, and to use at the local boards cords which distinguish between common battery and magneto lines. This method has its disadvantages in that there is no direct super-' vision from the toll cord, thelocal. operator supervising all connections. On toll connections it is important that all supervision Specification of Letters Patent.

Application filed June 12, 1915.

Patented Nov. 23, 1915.

Serial No. 33,725. 7

from magneto and common battery lines.

the trunks being plug-ended at the local board and adapted for connection directly with the local lines. Such a method is open to the objection that the trunks cannot be multipled through the toll board, for all supervisory signals are associated directly with the trunks.

While the scheme of multipling all local lines through the various positions of the toll board is an excellent one, still it means a high first cost for equipment.

In accordance with this invention, the common battery and magneto telephone lines terminate at regular subscribers positions of a switchboard, while the toll lines terminate at a toll position of the same board or at a different switchboard located in either the same or a different central oflice. Extending between the local and the toll position is a trunk circuit, plug-ended at the local board for connection to either a common battery or a magneto telephone line. At the toll position is a toll link connecting circuit for connecting a toll line with a trunk circuit. Supervisory signals associated with the toll link circuit are controlled from the common battery and magneto telephone lines through the agency of apparatus located in the trunk and toll link circuits.

This invention will be more fully understood by reference to the accompanying drawing illustrating one embodiment of the invention and wherein all apparatus is shown in its normal and unactuated condition.

In the drawing there is shown a common battery substation A and a magneto substation B, both terminating in a localposition C of the switchboard. A trunk circuit D extends from the local position G to a toll po sition E. At the toll position is located a toll'cord circuit F. For the purpose of the v presentinvention', only one end of the cord circuit is showm'the other end ofthecord circuit and the toll lines, to which it is adapt- I the operator at position E inserts the plug of the cord circuit F into the jack of the trunk circuit D, whereupon relay5 operates, lighting both supervisory signals 6 and '7 the former located at thetoll position E and the latter at the local position G. The operation of relay 5 bythe opening of contact 31 disconnects ,relay 15. from the ring side of the trunk circuitD. The energizing circuit of relay 5 includes the winding of relay 8 .and supervisory lamp 9 in parallel. The resistance of the two windings of relay 5 is such that relays is notlactuated and supervisory lamp19 is not lighted. Insertion of the plug into the- :jack -.o,pens contact 30, whereby the g ound connection is removed from the tip side of the trunk circuit ,1). The operator at position G, observing the; signal 7 actuate's listening key 10, bridging the operators telephone set across the talking strands of the trunk circuit, and operating relay 1'5 overfa circuit from battery 16 through the n ing of relay 15, contact 17 of relay 5,

contact 18 of listeningfke'y LOto ground;

lay 1.5. i operating, completes a locking circuit for itself which be traced from battery 16,, winding of relay 1.5, Contact 17 of relay 5 and contact 19 of relay 15 to ground. The operator at positionEhaving thrown listening key 11 .thereat the operator at position C may receive instructions from the operator at position IE asto the number of the wanted line. The operator at position .0, having .beenfadvised that the trunk is tobe connectedto.subscriber As line, releases listening key 10 and inserts the plug of the trunk G into the jacket As line whereupon relay 20 operates. Relay 20 in operating, short-circuits the right-hand winding of relay 5, thereupon lowering the resistance .of the operating strand of the toll 5 end of the trunk c1rcu1t D to such an extent that relay 8operates toconnect a battery to the talkingstrandskof the cord circuit F through the windings of relay 25, and supervisory lamp 9 lights to furnish a ringing signal to the toll operator. The called subscriber may now be signaled by the toll operator in the usual manner, When responding, the called subscriber, in removing the receiyer from the switch hoolr, causes the operation of relay 25 which efiacessupervisory'signal .9. When the conversation is completed, subscriber A restores the receiver to the 's itchhook, whereupon -.supervisory signal ,9 lights to furnish a. disconnect signal is a? reeer seesa :area

tion E, in removing the plug of the cord from the jack of the trunk circuit, deencrgizes relay 5, whereupon signals 6 and 7 are actuated, signal 7 furnishing a disconnect signal to the local operator. The circuit through the signals 6 and 7 includes contact 26 of relay 5 and contact 27 of relay 20. The operator at position C may now remove the plug from the jack of As line, whereupon all apparatus returns to its normal condition.

If it had been desired to complete the con.- nect-ion to subscriber B instead of to sub scriber A, the operations would have been the same up to the point where the operator at position C inserts the plug of trunk circuit D into the jack of the called line. The insertion .of the plug into the jack of Us line does not operate relay 20 for the sleeve circuit of Bs-line is open. Subscriber B maybe signaled in the usual manner. When the conversation is completed, subscriber B gives a disconnect signal to the operator at position F by operating the generator E28 which causes the operation of disconnect signal 29. The operator at position F re moves the plug from the jack, whereupon relay 5 is deenergized as before explained. The removal .of the plug from the jack also closes contact 30, whereupon relay 15 is actuated over'a circuit which may be traced from battery 16, through the winding of relav 1.5, contact 31 of relay 5, out over one side of the line through the call bell 32 at station B,.and back over the other side of the line to ground through contact 30. The operation of relay 15 causes the operation of signals (3 and 7., the circuit for these being closed at contact 26 of relay 5 and contact 19 of relay 15. The operator at position C observing disconnect signal 7, may now remove the plug in the usual manner, whereupon all up paratus is returned to normal condition.

Should subscriber A initiate .a call, the operator at position C is signaled in the usual manner, whereupon :the call is answered in the usual manner by inserting the answer-- ing plug of a cord circuit (not shown). The operator ascertaining that a toll connection is desired, withdraws the answering plug of thecord and inserts the plug of the trunk circuit D into the jack of the line, causing the operation of relay 20 which short circuits the right hand winding of relay 5 and causes the operation of signals 6 and 7. Relay 15 also operates but performs no function where subscriber A initiates a call. The toll operator at position E observing signal 6, inserts the plug of cord circuit F into the jack of the trunk circuit tr e see a ta es reissue t e an eration of supervisory lamp 9. The operator at. position E, after receiving theproper instructions completes the connection in the usual manner. lVhen the con versation is completed subscriber A restores the receiver to the switchhook whereupon supervisory signal 9 at position E operates to furnish a disconnect signal. The connections may be taken down in the'manner hereinbefore explained. I

Should subscriber B initiate the call, the central oftice is signaled in the usual manner, whereupon the operator answers by inserting the plug into the jack of Bs line. Relay 15 is thereupon energized over a cir cuit including the line wires and contact 30 of the jack of the trunk D. The operation of relay 15 causes the operation of the signals e and 7. The operator at position E, observing signal 6, inserts the plug of cord circuit F into the jack of trunk circuit D, thereby operating relay 5 which eii'aces signals 6 and 7. The connections then may be completed by the operator at position E in the usual manner. When the conversation is completed, subscriber B operates the generator 28 which actuates the disconnect signal The operators at positions E and C then take down the connections in the manner hereinbefore explained.

It will be seen that by using a system embodying the present invention a single trunk circuit may be used for completing the connections from both common battery and magneto lines to a toll position and from a toll position to both common battery and magneto lines. Also that the operator at the toll position has entire supervision over the connection established from a toll line to either a common battery or magneto ,line.

What is claimed is:

1. In a telephone exchange system, different types of telephone lines terminating at a local position of a switch-board, a trunk circuit extending from the local position to a second position, a link circuit adapted at said second position for connection with said trunk circuit, a supervisory signal associated with said link circuit, and switching means associated with said trunk circuit operating upon connection oi said trunk circuit with a predetermined type of line for placing said supervisory signal under control of the connected line when said link and trunk circuits are connected.

2. In a telephone exchange system, different types of telephone lines terminating at a local position of a. switchboard, a trunk circuit extending from the local position to a toll position, a toll link circuit adapted for connection with said trunk circuit, supervisory signals of different character associated with said toll link circuit, and switclr ing means associated with said trunk circuit operating upon connection of said trunk air cuit with a predetermined type of line for placing one of said supervisory signals of the connected link circuit under control of the connected line.

3. In a telephone exchange system, common battery and magneto telephone lines terminating at a local position of a switchboard, a trunk circuit extending from the local position to a toll position, a toll linkcircuit adapted for connection with said trunk circuit, two supervisory signals of different character assoclated with said link circuit, and switching means associated with circuit extending from the local position to a toll position, a toll link circuit adapted for connection with said trunk circuit, two supervisory signals associated with said toll link circuit, an operating strand for the toll end of said trunk circuit, a relay associated with said trunk circuit operating upon connection of said trunk circuit with a predetermined type of line to alter the re sistance of said operating strand, and a relay associated with said link circuit responsive to the altered condition of said operating strand when said link circuit is connected with said trunk circuit, the actuation of said link circuit relay placing one of said supervisory signals under control of the connected telephone line.

In a telephone exchange system, different types of telephone lines terminating at a local position of a switchboard, a trunk circuit extending from the local position to a toll position, an operating strand for the toll end of said trunk circuit, and switching means associated with the local position end of said trunk and operating when said trunk is connected to a predetermined type of line to reduce the resistance of said operating strand, a toll link circuit adapted for connection with said trunk circuit,asupervi sory signal and a relay associated with said link circuit, and a circuit for said relay including said operating strand, the reduced resistance of said operating strand permitting the operation of said relay whereby when said link circuit is connected with said trunk circuit said relay operates to place said supervisory signal under control of the connected line.

6. In a telephone exchange system, different types of telephone lines terminating ond position adapted for connection With said trunk circuit, and switching means ass0c1atecl with sand trunk circult operatlng upon' connection of said trunk circuit With a predetermined type of line for rendering said connected link circuit operable with the precletetmine'cl type of telephone line. 10 In Witness whereof I hereunto subscribe my name this 11th day of June, A. D. 1915.

EDWARD E. HINRICHSEN.

Ccpiesof this liatent may be obtained for five cents each, by addressing the Commissioner of Patents. 7 Washington, D. G. 

